Phonograph



a. B. BURCH PHONOGRAPH Aug. 26 1924.

Filed March 8,: 1918 2 Sheets-Sheet 2 Patented Aug. 26 1924. 1

UNITED STATES GEORGE B. BUR-CH, or NEW YORK, N. Y.,

ASSIGNOR T LESLIE STEVENS, OF GLEN RIDGE, NEW JERSEY.

rHonoGRArrr.

To all whom it may concern:

Be it known that I, GEORGE B. BU'ROH, a citizen of the United States, and a resident of the city of New York, county of Kings, and State of New York, have invented a inew. and useful Improvement in Phonographs, of which the following is a specifi cation. I

The object of my invention is to provide a simple device of this class which will be simple in construction and accurate and re- -'-liable in operation. This object is accompli'shed by my invention, one embodiment of which is hereinafter more particularly set forth;

For a more particular description of my invention, reference is to be had to the accompanying drawings, formingapart hereof, in'whioh,- Figure 1 is'a sectional view of a structure embodying my invention, I

Figure 2 is a sectional view of a diaphragm,

Figure 3 is a view, partially in section,

showing the needle and some attached and connected parts.

Throughout the various views of the drawings, similar reference characters designate similar parts.

My improved phonograph 1 is provided with a'casing 2, a suitable motor 3, from =Which extends u wardly 'a spindle 4 on which is mounted a table 5 of the conventional kind, which carries a record 6 in the usual manner.

At one side of the table 5 is placed a bracket 7 which has a hinge 8 pivoted therein and a pair of rings 9 affixed to the hinge 8 and these have the free edge of a diaphragm 10 sandwiched in between them.

The diaphragm is a large, direct-acting, diaphragm requiring no amplifying device, that is, it is of'a size to produce sounds of the desired volume by setting upsound waves directly in the surrounding atmosphere. A.

size of from nine inches to a foot in diamr eter-has been found most desirable for phonogra h reproducers. The diaphragm is of conoi a1 form, its outer surface, that is, the

' surface on the bulging,'or-convex, side of the diaphragm, being concavely curved from the 'apex' of the diaphragm outward in all Application filed March 8, 1918. Serial No. 221,285.

radial directions. The central portion ofthe diaphragm is thicker than the portions nearer its periphery.

Near the rings 9, it is provided with a gutter 11 which is thin compared with the center so as to permit the diaphragm to re spond accurately to vibrations which may be imparted to it by a needle bar 12 which is fixed to the diaphragm 10 by a proper means.

The needle bar 12 is mounted in a tube 13 .by means of the perforated washers 14 and or any other suitable form. This holder is also provided with a laterally extending collar 20 which is engaged by a coil spring 21 which presses against this shoulder and also against the washer 15, as indicated. This spring 21 is a compression spring which performs the function of holding the needle holder 17 at all times true upon the needle bar 12. i

The tube 13 is supported from the rings 9 by means of a spider 22 having laterall extending arms 23 that'are secured to the rings 9by screws 24 and washers 25.

In view of the foregoing, the operation of my improved phonograph will be readily understood. Assuming the parts to be as shown in Figure 1, and the table 5 turning in the conventional manner, sound vibrations are transmitted along the needle bar 12 to the diaphragm 10 at the center, the dlaphragm being thereby caused to vibrate and to set up the desired sound waves in the surrounding or adjacent atmosphere.

While I have shown and described one embodiment of my invention, it is obvious that it is not restricted thereto, but is broad enough to cover all structures that come within the scope of the annexed. claims. What I claim is: 1. An acoustic device, comprising a large, direct-acting vibratory diaphragm of coulOO oidal form the outer surface of which is condiaphragm being thicker than the portions cavely curved from its apex outward in all nearer its periphery. 1 radial directions. 3. A sound reproducer, comprising a 2. An acoustic device, comprising a large, large, direct-acting vibratory diaphragm of 5 direct-acting vibratory diaphragm of conconoidal form the outer surface of which is oidal form the outer surface of which is conconcavely curved from its apex outward in cavely curved from its apex outward in all all radial directions.

radial directions, the central portion of the GEORGE B. BURCH. 

